This invention relates to a vehicle wheel for automobiles such as passenger cars, trucks, buses and motor cycles, and more particularly to a modified wheel rim for such vehicles.
Most automobile wheels have rims which are manufactured to an internationally recognized standard, an example of which is shown in FIG. 1 of the accompanying drawings where the rim is attached to a central disk to form the wheel. The purpose of the standardized rim profile is to provide compatibility with the specifically designed tire sizes and also to ensure that adequate provision is also made for the mounting and demounting of tires to and from the rim.
Historically these international rim standards were based on rim profiles that were originally developed by the then current manufacturing processes i.e., rolling wrought steel strips into a suitable rim profile and butt welding into a circular wheel rim. The outer profile of the rim thus closely follows the internal profile of the rim resulting in a rim profile which is virtually standard on all wheels. Cover plates, wheel trims, hub caps or the like have been developed to improve the aesthetic appearance of a wheel, often by clipping onto the outer edge of the rim so that the entire rim profile is hidden.
However today there are many processes by which automobile wheels can be manufactured, including stamping, pressing drawing, roll forming, forging, moulding and casting, some of which may allow for the adoption of a modified rim profile which still meets the basic requirements for tire mounting and compatibility. It is essential that the internal configuration of the wheel rim meet the international standards for the support of the bead of the tire and the mounting and demounting of the tire.
If the profile of the outer surface of the rim portion of the wheel rim is to be changed, for example in making the outer profile rounded or curved in some way, the result could appear as shown in FIGS. 2 and 3. FIG. 2 depicts a motor car wheel having a rounded outer surface of the wheel rim, that is the outer surface which is outermost of the vehicle, and FIG. 3 showing a motor cycle wheel in which both sides of the rim are rounded. These wheel rims while being of pleasing appearance may have manufacturing problems, but also have the greater disadvantage of being unduly heavy, there being a greater mass in the rim of the wheel. This greatly increases the unsprung weight of the suspension and detracts from the ride, handling and road holding characteristics of the vehicle.
Reference is also made to U.S. Pat. Nos. 4,854,646 and 5,749,982 which show various wheel rim profiles, the outer contours of which follow the internal profile of the rim. Australian patent specification shows a further wheel rim in which the outer profile follows the internal profile of the rim, a further example being shown in Australian Registered Design No 66313.